diff --git a/.cargo_vcs_info.json b/.cargo_vcs_info.json
index e5ef5a3..5809fb6 100644
--- a/.cargo_vcs_info.json
+++ b/.cargo_vcs_info.json
@@ -1,5 +1,5 @@
 {
   "git": {
-    "sha1": "636cde7a9e61447c6f17f8cc665c32e7f70f319f"
+    "sha1": "d0e0ab4cb4e060c37bfcbb0c2eebe1325186cad6"
   }
 }
diff --git a/.github/workflows/clippy-check.yml b/.github/workflows/clippy-check.yml
new file mode 100644
index 0000000..6010bf2
--- /dev/null
+++ b/.github/workflows/clippy-check.yml
@@ -0,0 +1,12 @@
+on: push
+name: Clippy check
+jobs:
+  clippy_check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+      - run: rustup component add clippy
+      - uses: actions-rs/clippy-check@v1
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          args: --all-features
diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
new file mode 100644
index 0000000..7a261ad
--- /dev/null
+++ b/.github/workflows/rust.yml
@@ -0,0 +1,89 @@
+on: [push, pull_request]
+
+name: Continuous integration
+
+jobs:
+  check:
+    name: Check
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        rust:
+          - stable
+          - 1.44.0
+          - nightly
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: ${{ matrix.rust }}
+          override: true
+      - name: Cargo update
+        run: cargo update
+      - uses: actions-rs/cargo@v1
+        with:
+          command: check
+
+  test:
+    name: Test Suite
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+      - uses: actions-rs/cargo@v1
+        with:
+          command: test
+
+  fmt:
+    name: Rustfmt
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+      - run: rustup component add rustfmt
+      - uses: actions-rs/cargo@v1
+        with:
+          command: fmt
+          args: --all -- --check
+
+  clippy:
+    name: Clippy
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+      - run: rustup component add clippy
+      - uses: actions-rs/cargo@v1
+        with:
+          command: clippy
+          args: -- -D warnings
+
+  doc:
+    name: Build documentation
+    runs-on: ubuntu-latest
+    env:
+      RUSTDOCFLAGS: --cfg docsrs
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: nightly
+          override: true
+      - uses: actions-rs/cargo@v1
+        with:
+          command: doc
+          args: --workspace --no-deps --all-features
diff --git a/.github/workflows/security-audit.yml b/.github/workflows/security-audit.yml
new file mode 100644
index 0000000..7641204
--- /dev/null
+++ b/.github/workflows/security-audit.yml
@@ -0,0 +1,15 @@
+name: Security audit
+on:
+  schedule:
+    - cron: "0 8 * * *"
+  push:
+    paths:
+      - "**/Cargo.*"
+jobs:
+  security_audit:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+      - uses: actions-rs/audit-check@v1
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
diff --git a/Android.bp b/Android.bp
index 7c15e72..cdc6399 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,8 +1,6 @@
 // This file is generated by cargo2android.py --config cargo2android.json.
 // Do not modify this file as changes will be overridden on upgrade.
 
-
-
 package {
     default_applicable_licenses: [
         "external_rust_crates_rusticata-macros_license",
@@ -45,6 +43,8 @@
     name: "librusticata_macros",
     host_supported: true,
     crate_name: "rusticata_macros",
+    cargo_env_compat: true,
+    cargo_pkg_version: "4.0.0",
     srcs: ["src/lib.rs"],
     edition: "2018",
     rustlibs: [
@@ -56,6 +56,8 @@
     name: "rusticata-macros_test_defaults",
     crate_name: "rusticata_macros",
     srcs: ["src/lib.rs"],
+    cargo_env_compat: true,
+    cargo_pkg_version: "4.0.0",
     test_suites: ["general-tests"],
     auto_gen_config: true,
     edition: "2018",
diff --git a/Cargo.toml b/Cargo.toml
index 1f5f076..def8c45 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,7 +13,7 @@
 [package]
 edition = "2018"
 name = "rusticata-macros"
-version = "3.1.0"
+version = "4.0.0"
 authors = ["Pierre Chifflier <chifflier@wzdftpd.net>"]
 description = "Helper macros for Rusticata"
 homepage = "https://github.com/rusticata/rusticata-macros"
@@ -23,4 +23,6 @@
 license = "MIT/Apache-2.0"
 repository = "https://github.com/rusticata/rusticata-macros.git"
 [dependencies.nom]
-version = "6.0"
+version = "7.0"
+features = ["std"]
+default-features = false
diff --git a/Cargo.toml.orig b/Cargo.toml.orig
index 6c23803..983518e 100644
--- a/Cargo.toml.orig
+++ b/Cargo.toml.orig
@@ -1,6 +1,6 @@
 [package]
 name = "rusticata-macros"
-version = "3.1.0"
+version = "4.0.0"
 description = "Helper macros for Rusticata"
 license = "MIT/Apache-2.0"
 keywords = ["parser","nom","serialize"]
@@ -12,4 +12,4 @@
 readme = "README.md"
 
 [dependencies]
-nom = "6.0"
+nom = { version = "7.0", default-features = false, features = ["std"] }
diff --git a/METADATA b/METADATA
index ddd8570..7793cf9 100644
--- a/METADATA
+++ b/METADATA
@@ -7,14 +7,13 @@
   }
   url {
     type: ARCHIVE
-    value: "https://static.crates.io/crates/rusticata-macros/rusticata-macros-3.1.0.crate"
+    value: "https://static.crates.io/crates/rusticata-macros/rusticata-macros-4.0.0.crate"
   }
-  version: "3.1.0"
-  # Dual-licensed, using the least restrictive per go/thirdpartylicenses#same.
+  version: "4.0.0"
   license_type: NOTICE
   last_upgrade_date {
     year: 2021
-    month: 7
-    day: 9
+    month: 9
+    day: 22
   }
 }
diff --git a/README.md b/README.md
index 6defe1e..42cd1fd 100644
--- a/README.md
+++ b/README.md
@@ -36,8 +36,9 @@
 
 Different versions of this crate are available, depending on nom version.
 
-- `rusticata-macros` 0.3.x depends on nom 6
-- `rusticata-macros` 0.2.x depends on nom 5
+- `rusticata-macros` 4.x depends on nom 7
+- `rusticata-macros` 3.x depends on nom 6
+- `rusticata-macros` 2.x depends on nom 5
 
 ## Documentation
 
@@ -47,6 +48,11 @@
 
 ## Changes
 
+### 4.0.0
+
+- Upgrade to nom 7
+  - Remove macros
+
 ### 3.0.1
 
 - Add `be_var_u64` and `le_var_u64`
diff --git a/benches/bench.rs b/benches/bench.rs
index 250f5be..454625b 100644
--- a/benches/bench.rs
+++ b/benches/bench.rs
@@ -5,13 +5,13 @@
 
 extern crate rusticata_macros;
 
-use rusticata_macros::bytes_to_u64;
+use rusticata_macros::combinator::be_var_u64;
 
 #[bench]
 fn bench_bytes_to_u64(b: &mut Bencher) {
     let bytes = &[0x12, 0x34, 0x56, 0x78, 0x90, 0x12];
     b.iter(|| {
-        let res = bytes_to_u64(bytes);
-        assert_eq!(res, Ok(0x123456789012));
+        let res = be_var_u64::<()>(bytes).unwrap();
+        assert_eq!(res.1, 0x123456789012);
     });
 }
diff --git a/src/combinator.rs b/src/combinator.rs
index f5de774..d542557 100644
--- a/src/combinator.rs
+++ b/src/combinator.rs
@@ -3,10 +3,32 @@
 use nom::bytes::streaming::take;
 use nom::combinator::map_parser;
 pub use nom::error::{make_error, ErrorKind, ParseError};
-pub use nom::{IResult, Needed};
+pub use nom::{IResult, Needed, Parser};
 use nom::{InputIter, InputTake};
 use nom::{InputLength, ToUsize};
 
+#[deprecated(since = "3.0.1", note = "please use `be_var_u64` instead")]
+/// Read an entire slice as a big-endian value.
+///
+/// Returns the value as `u64`. This function checks for integer overflows, and returns a
+/// `Result::Err` value if the value is too big.
+pub fn bytes_to_u64(s: &[u8]) -> Result<u64, &'static str> {
+    let mut u: u64 = 0;
+
+    if s.is_empty() {
+        return Err("empty");
+    };
+    if s.len() > 8 {
+        return Err("overflow");
+    }
+    for &c in s {
+        let u1 = u << 8;
+        u = u1 | (c as u64);
+    }
+
+    Ok(u)
+}
+
 /// Read the entire slice as a big endian unsigned integer, up to 8 bytes
 #[inline]
 pub fn be_var_u64<'a, E: ParseError<&'a [u8]>>(input: &'a [u8]) -> IResult<&'a [u8], u64, E> {
@@ -70,29 +92,28 @@
 }
 
 /// Return a closure that takes `len` bytes from input, and applies `parser`.
-pub fn flat_take<I, C, O, E: ParseError<I>, F>(len: C, parser: F) -> impl Fn(I) -> IResult<I, O, E>
+pub fn flat_take<I, C, O, E: ParseError<I>, F>(
+    len: C,
+    mut parser: F,
+) -> impl FnMut(I) -> IResult<I, O, E>
 where
     I: InputTake + InputLength + InputIter,
     C: ToUsize + Copy,
-    F: Fn(I) -> IResult<I, O, E>,
+    F: Parser<I, O, E>,
 {
     // Note: this is the same as `map_parser(take(len), parser)`
     move |input: I| {
         let (input, o1) = take(len.to_usize())(input)?;
-        let (_, o2) = parser(o1)?;
+        let (_, o2) = parser.parse(o1)?;
         Ok((input, o2))
     }
 }
 
 /// Take `len` bytes from `input`, and apply `parser`.
-pub fn flat_takec<I: Clone, O, E: ParseError<I>, C, F>(
-    input: I,
-    len: C,
-    parser: F,
-) -> IResult<I, O, E>
+pub fn flat_takec<I, O, E: ParseError<I>, C, F>(input: I, len: C, parser: F) -> IResult<I, O, E>
 where
     C: ToUsize + Copy,
-    F: Fn(I) -> IResult<I, O, E>,
+    F: Parser<I, O, E>,
     I: InputTake + InputLength + InputIter,
     O: InputLength,
 {
@@ -100,21 +121,21 @@
 }
 
 /// Helper macro for nom parsers: run first parser if condition is true, else second parser
-pub fn cond_else<I: Clone, O, E: ParseError<I>, C, F, G>(
+pub fn cond_else<I, O, E: ParseError<I>, C, F, G>(
     cond: C,
-    first: F,
-    second: G,
-) -> impl Fn(I) -> IResult<I, O, E>
+    mut first: F,
+    mut second: G,
+) -> impl FnMut(I) -> IResult<I, O, E>
 where
     C: Fn() -> bool,
-    F: Fn(I) -> IResult<I, O, E>,
-    G: Fn(I) -> IResult<I, O, E>,
+    F: Parser<I, O, E>,
+    G: Parser<I, O, E>,
 {
     move |input: I| {
         if cond() {
-            first(input)
+            first.parse(input)
         } else {
-            second(input)
+            second.parse(input)
         }
     }
 }
diff --git a/src/debug.rs b/src/debug.rs
index eb4e821..ec8977b 100644
--- a/src/debug.rs
+++ b/src/debug.rs
@@ -1,7 +1,15 @@
 //! Helper functions and structures for debugging purpose
 
+use nom::combinator::{map, peek, rest};
+use nom::HexDisplay;
+use nom::IResult;
 use std::fmt;
 
+/// Dump the remaining bytes to stderr, formatted as hex
+pub fn dbg_dmp_rest(i: &[u8]) -> IResult<&[u8], ()> {
+    map(peek(rest), |r: &[u8]| eprintln!("\n{}\n", r.to_hex(16)))(i)
+}
+
 /// Wrapper for printing value as u8 hex data
 pub struct HexU8(pub u8);
 
diff --git a/src/lib.rs b/src/lib.rs
index c6f4344..119ea48 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,24 +4,20 @@
 //!
 //! This crate contains some additions to [nom](https://github.com/Geal/nom).
 //!
-//! For example, the `error_if!` macro allows to test a condition and return an error from the parser if the condition
-//! fails:
+//! For example, the [`cond_else`] function allows to apply the first parser if the
+//! condition is true, and the second if the condition is false:
 //!
 //! ```rust
-//! # extern crate rusticata_macros;
-//! # extern crate nom;
-//! # use nom::{do_parse, take, IResult};
-//! # use nom::error::ErrorKind;
-//! # use nom::number::streaming::be_u8;
-//! use rusticata_macros::error_if;
+//! # use nom::IResult;
+//! # use nom::combinator::map;
+//! # use nom::number::streaming::*;
+//! use rusticata_macros::combinator::cond_else;
 //! # fn parser(s:&[u8]) {
-//! let r : IResult<&[u8],()> = do_parse!(
-//!     s,
-//!     l: be_u8 >>
-//!     error_if!(l < 4, ErrorKind::Verify) >>
-//!     data: take!(l - 4) >>
-//!     (())
-//!     );
+//! let r: IResult<_, _, ()> = cond_else(
+//!         || s.len() > 1,
+//!         be_u16,
+//!         map(be_u8, u16::from)
+//!     )(s);
 //! # }
 //! ```
 //!
@@ -35,7 +31,6 @@
     unused_qualifications
 )]
 
-#[macro_use]
 extern crate nom;
 
 extern crate core;
diff --git a/src/macros.rs b/src/macros.rs
index c74cb4e..6109162 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -2,9 +2,7 @@
 
 use nom::bytes::complete::take;
 use nom::combinator::map_res;
-use nom::combinator::rest;
 pub use nom::error::{make_error, ErrorKind, ParseError};
-use nom::HexDisplay;
 pub use nom::{IResult, Needed};
 
 #[doc(hidden)]
@@ -104,31 +102,6 @@
   );
 );
 
-/// Helper macro for nom parsers: run first parser if condition is true, else second parser
-#[macro_export]
-macro_rules! cond_else (
-  ($i:expr, $cond:expr, $expr_then:ident!($($args_then:tt)*), $expr_else:ident!($($args_else:tt)*)) => (
-    {
-      if $cond { $expr_then!($i, $($args_then)*) }
-      else { $expr_else!($i, $($args_else)*) }
-    }
-  );
-  ($i:expr, $cond:expr, $expr_then:expr, $expr_else:ident!($($args_else:tt)*)) => (
-      cond_else!($i, $cond, call!($expr_then), $expr_else!($($args_else)*))
-  );
-  ($i:expr, $cond:expr, $expr_then:ident!($($args_then:tt)*), $expr_else:expr) => (
-      cond_else!($i, $cond, $expr_then!($($args_then)*), call!($expr_else))
-  );
-  ($i:expr, $cond:expr, $expr_then:expr, $expr_else:expr) => (
-      cond_else!($i, $cond, call!($expr_then), call!($expr_else))
-  );
-);
-
-/// Dump the remaining bytes to stderr, formatted as hex
-pub fn dbg_dmp_rest(i: &[u8]) -> IResult<&[u8], ()> {
-    map!(i, peek!(call!(rest)), |r| eprintln!("\n{}\n", r.to_hex(16)))
-}
-
 #[deprecated(since = "3.0.1", note = "please use `be_var_u64` instead")]
 /// Read an entire slice as a big-endian value.
 ///
@@ -288,7 +261,7 @@
 mod tests {
     use nom::error::ErrorKind;
     use nom::number::streaming::{be_u16, be_u32, be_u8};
-    use nom::{Err, IResult, Needed};
+    use nom::{error_position, Err, IResult, Needed};
 
     #[test]
     #[allow(unsafe_code)]
@@ -325,34 +298,6 @@
     }
 
     #[test]
-    fn test_cond_else() {
-        let input = &[0x01][..];
-        let empty = &b""[..];
-        let a = 1;
-        fn parse_u8(i: &[u8]) -> IResult<&[u8], u8> {
-            be_u8(i)
-        }
-        assert_eq!(
-            cond_else!(input, a == 1, call!(parse_u8), value!(0x02)),
-            Ok((empty, 0x01))
-        );
-        assert_eq!(
-            cond_else!(input, a == 1, parse_u8, value!(0x02)),
-            Ok((empty, 0x01))
-        );
-        assert_eq!(
-            cond_else!(input, a == 2, parse_u8, value!(0x02)),
-            Ok((input, 0x02))
-        );
-        assert_eq!(
-            cond_else!(input, a == 1, value!(0x02), parse_u8),
-            Ok((input, 0x02))
-        );
-        let res: IResult<&[u8], u8> = cond_else!(input, a == 1, parse_u8, parse_u8);
-        assert_eq!(res, Ok((empty, 0x01)));
-    }
-
-    #[test]
     fn test_newtype_enum() {
         #[derive(Debug, PartialEq, Eq)]
         struct MyType(pub u8);